Beginning in 1995 Judson worked for two years as a science writer for The Economist and she later joined Imperial College London, where she is now an honorary research fellow. In 1997, she wrote an Economist article named "Sex Is War!" which was awarded the Glaxo Wellcome Prize by the British Science Writers Association.[1]

Her first book, Dr Tatiana's Sex Advice to All Creation (2002), grew out of that article. Written in the style of a sex-advice column to animals, the book details the variety of sexual practices in the natural world and provides the reader with an overview of the evolutionary biology of sex. The book was praised by critics as being witty and engaging, without compromising its scientific integrity. It became an international best-seller and was nominated for the Samuel Johnson Prize for Non-Fiction in 2003.[1]

Judson has also worked as a television presenter. In 2004 she played Dr Tatiana in an adaptation of her book; the series was produced by Wag TV and EPI Productions for Channel 4 and Discovery Canada. In 2007 she co-presented Animal Farm with Giles Coren; the series, which explored genetic modification and pharming, was produced by Lion Television for Channel 4.

Judson is a former on-line columnist for the New York Times. In 2014 she did a series of eight blogs, after a four-year hiatus.[17] In January 2008, Judson began writing a weekly blog on evolutionary biology, titled "The Wild Side", for The New York Times website. For the first half of 2009, guest bloggers filled in for Judson while she worked on a new book, Dinosaur Eggs for Breakfast, and she then had been on a "sabbatical" from blogging beginning June 29, 2010.[18]

In 2009, she appeared in an episode of PBS's Nova called "What Darwin Never Knew" which discussed DNA connections to evolution.

^Judson, O.; Haydon, D. (1999). "The genetic code: What is it good for? An analysis of the effects of selection pressures on genetic codes". Journal of Molecular Evolution. 49 (5): 539–550. doi:10.1007/PL00006575. PMID10552035.